The prior art hammer-solenoid systems disclose that to control the volume or expression, (how hard the instrument is struck) the voltage at which the solenoids are energized is varied to control the energy transferred to the instrument to re-create musical notes with the original artist's expression. In one known case, the expense to control the drive to each note would be prohibitive for producing units. There also is the question that, if sensing the volume of piano after the key is struck and then playing back, the correct timing exists to allow the volume to control the solenoid drive.
The object of the present invention is to provide a more faithful rendition of the recorded expression effects of a musical presentation.